1. Field of the Invention
This invention relates generally to an applicator for dispensing a mixture of first and second component fluids for medical and other applications, and more particularly, to an apparatus and method for applying a biological adhesive to tissues or organs for sealing wounds and stopping bleeding or to coat prosthetic devices, the apparatus adapted for use with rechargeable or disposable cartridges containing a biologically compatible compressed gas, and further having reservoirs for the first and second components with luer connectors to facilitate attachment to a supply of the first and second components.
2. Description of Related Art
Biological adhesives, such as fibrin sealants, are used to seal wounds and stop bleeding. The components of fibrin sealants include a solution containing thrombin and a solution containing fibrinogen. The solution containing thrombin generally has a relative viscosity of approximately 1.0. The solution containing fibrinogen, on the other hand, can have various relative viscosities depending upon the concentration of fibrinogen. Along those lines, U.S. Pat. No. 2,533,004 to Ferry is directed to various fibrin sealants using different concentrations of fibrinogen and thrombin solutions. Accordingly, an applicator must effectively dispense components having various viscosities. Furthermore, due to the varying viscosities of the solutions, as well as the need for varying adhesive properties, the proportion of the thrombin solution dispensed in relation to the dispensed fibrinogen solution must be controllable.
Although various types of applicators for fibrin sealant have previously been used, such prior applicators have failed to incorporate any structure and method for varying the dispensed proportions of the thrombin solution relative to the fibrinogen solution. U.S. Pat. No. 4,735,616 to Eibl et al. is directed to an arrangement for applying a biological adhesive. The Eibl arrangement includes syringe bodies having equal effective strokes yet different cross-sectional areas. Due to the difference in cross-sectional areas of the two syringes, the ratio of fluid in one syringe that is dispensed relative to the amount of fluid in the second syringe that is dispensed does not equal 1. The device does not allow varying proportions of the fluid to be dispensed. In order for different proportions of the fluids to be dispensed, the syringe must be replaced with another syringe having a different cross-sectional area. As such, these earlier devices prove to be quite cumbersome in use.
Furthermore, previous applicators for dispensing a biological adhesive require the manual exertion of a force on the components so that they may be expelled from the applicator. Typically, a manual force is exerted on the components by means of a standard one-way syringe. This type of arrangement is shown in U.S. Pat. Nos. 4,359,049 and 4,631,055 to Redl et al. Although the embodiments of Redl et al. utilize a pressurized gas, the devices disclosed therein require a manual force to expel the adhesive as the gas is used to merely atomize the adhesive. See U.S. Pat. No. 4,631,055 Col. 3, lines 41-48; U.S. Pat. No. 4,359,049 Col 3, lines 54-57. Manually exerting a force on the components can make application of the adhesive awkward, imprecise, and wasteful.
Similarly, although a syringe-type arrangement is avoided in U.S. Pat. No. 4,902,281 to Avoy, that patent requires a manually exerted force to be applied to the adhesive components. The Avoy patent is directed to the use of a pumping mechanism to expel the adhesive components from the applicator. In order to achieve the desired spray pattern, an abrupt depression of the pumping mechanism must be applied. Like the syringe arrangements, such an applicator is awkward, imprecise, and results in wasted adhesive.
Known devices for applying biological adhesives also have the disadvantage of being difficult to reuse. Once the various components that comprise the adhesive are used up, the supplies must be replenished. In an applicator using a syringe-type arrangement, such as disclosed in the U.S. Patents to Redl et al. discussed above, and in U.S. Pat. No. 4,979,942 to Wolf et al., replenishing the supply of components includes removing a clip which couples the two syringe plungers, detaching the syringes from a form of "Y" connector, removing the syringes from the holder, inserting new syringes, affixing the syringes to the "Y" connector, and replacing the plunger clip. In an application where time is of the essence, such a lengthy replenishing process is impractical and cumbersome.
The reloading procedure in U.S. Pat. No. 4,902,201 to Avoy is similarly inefficient and cumbersome. Replenishing the component solutions involves unlatching the door, opening the housing, removing the spent containers, replacing the containers and closing the housing. Like the replenishing procedure of the syringe-based applicators, this, too, is an involved, time consuming process.
Users of the known applicators encounter an additional difficulty when replenishing the supply of solutions. If a different combination of components is to be used in the applicator, the applications must be cleaned or, in a syringe-type arrangement, the "Y" connector must be replaced. Cleaning the applicator can be time consuming and replacing parts of the applicator is wasteful and non-economical.